Burglar alarm



Nov. 28, 1939. J. BECKER Er AL BURGLAR ALARM :'led April 29, 1931 mmm fizyenzof cfaf/zey'.

MMM-1l Zz;

y Patented Nov. l28,1939

, Unirse;sTArss BuRGtAn ALARM,

John C. Becker, Ormonde 1C. Becker, and EllsworthfJ.` Becker, Maywood, Ill., assignors' 'to Everett Experimental and' .Development Com- 3 pany, Shanghai, China; i

yrippiieatien Aprilv 29,1931, serial Ne. 533,727 f 12 claims.. (c1. 17u-.311) 4 f This invention relates to va'n apparatus and a method for detecting thejpresence of metal ob- While it has many applications, in the jects. form illustrated herewith one of the main objects is to provide whatis in effect a burglar alarm.

Another object of the invention is to provide means l for ,indicating the presence of .metal *ob-f Jects, such as revolvers and other weapons, on the persons of individuals entering buildings, passing through doors or coming into the rvicinity of the device. Another object is to` provide meansfor setting up a magnetic uX and for automatically detecting the presence of weapons upon the persons of individuals passing magnetic flux. y .p Y

yOtherr objects will appear from Vtime toi time `in the specification and claims. v y A' o The invention is illustrated more or less,` diagrammatically in the accompanying drawing,

wherein: l

Figure 1 is an elevation with parts broken away and parts in section, showing the apparatus in position about a singledoorway;

Figure 2 is a similar elevation showing the apparatusin position about a doubledoorwayj Figure3 is a wiring diagram `of one form of cir- J(Gruit for carrying out the method of, this invenlon. Like parts are designated bylike characters throughout the specification andr drawingl,"

As illustrated in Figure 1, the invention is .applied to a single doorway. Ainolicates a4 foundation or oor. A1 is a partition -or wall through which an opening or doorway A2 is formed.. A3 is a door frame of any suitable design. f k A Positioned in the door frame or near it'isa magnet B which is preferably a coil and provides a primary circuit. Positioned on the other side of the doorway is a coil ormagnet/B1y providing a secondary circuit. When the primary circuit is properly energized, a current is induced in the secondary circuit and a magneticflux is setup between the two. This is indicated diagrammatically in Figure 1 as at X. If a piece of metal or iron of sucient size is brought into the magneticA iiuX, it reduces the air gap and, therefore, shortens the distance through which the lines of torce; must pass. Consequently it increases the magnetcated at Y and the flux is indicated as divided into X1, X1. v i

As indicated in Figurez, the Wall A1 has two into orthrough such y is suicient that'primary and `secondary circuits kare set up,r and that the .primary circuitis propopenings-A4114 separated by a partition or dividing member A5, the two openings being-surroundedl by a multiple door frameA?. `The primary coil B of the primaryu circuit may be positioned on the dividing vmember" A5 and two secondary 'coils B131 of the 'secondary circuit may be positioned p on the sides-of ythe door." The coils, their method of construction andthe method of mounting may be varied. A single-magnetic coil may be used for eachofthe primaryorsecondary circuits or multiple; coils may beused. The detailsof construction and mounting ofv these parts formfn'o `Aparticular part ofthe present invention and it is not limited `to any particular construction. f It erly energized and that the two'fco-operate to produce the magnetic' iiuX across the gap.`

As indicated in Figure 3, there is shown one circuit suitable for carrying out` the invention.A Leads C, C1 are connected to a lsuitable source of alter- .nating current. These lead toa transformer C2 which is suitablyconnected by leadsCFiC3 to the primary coil or circuit B. The Secondarycoil or circuit B1is ,connected by-:lea'ds DD to a variable transformer D15y 2The transformer'is connected at one end by alead D2 to a lgrid D? of a `vacuum tube D4. At'its other end itis connected by alead D5 to a source. oi C current or C battery D6.v 'This latter is vconnected to one pole of an A battery yD7 which pole is also connected,l through a variable rheostat D5, to the filament D9 of the vacuum The other pole of the battery Dr1 is connected bya suitable lead D10 to the filament D? is connected by afleadE1 to the-plate E2 vof the vacuum tubeDfl;v The negative pole of the A battery DFI is connected by a lead E3rto. the negative lpele ef e B battery E4. The positive pcie ofthe B battery is connected-by a lead E5'to one pole of Aa polarized relay E6. 4From the -leadlii1 which is to one or more choke coils E", E1. From the second of these a connection is made to the opposite I pole of they polarized relay E6. f

. The various'elements of the circuit are normally balancedso that the movable memberE, of the polarized relay Eis held in the positionshown in Figure3.' n y' 7 F is a contact member adjacentthe movable member E,`positioned to be contacted 'by it. A lead F1.A connects the member F with a battery or source' ofcurrent F2. 1A lead F3 running from the opposite p ole oi the battery F2 connects the connected to the plate E2, a Aconnection is made latter to one pole of an annunciator F4. A lead F5 runs from the opposite pole of the annunciator F4 and is connected to a movably mounted contact arm F6 which is adapted, when free to do so, to make contact with a contact member F7 which is connected by a suitable lead F8 to the lead F1 and thus to the battery F2.

G is a contact memberpositioned adjacent the movable member E8 and generally opposite the contact member F. By means of a lead G1 it is connected to the lead F8.

H is a magnet which, by means of a lead H1 attached to one of its poles, is connected to the movable member E8. A lead H2 runs from the opposite pole of the magnet to the lead F3. H3 is a member positioned for movement and adapted to be drawn against the magnet when the latter is energized. The member H3 normally holds the movably mounted arm F6 out of engagement with the contact member F7, holding it in the position shown in Figure 3.

It will be realized that whereas we have herewith `shown and described a practical operative device, nevertheless many changes might be made in the size, shape, number and disposition of' parts without departing from the spirit of the invention and we wish, therefore, that our showing be taken as in a sense diagrammatic. In particular, many different circuits might be used for actuating the circuit andthe annunciator and for carrying out other steps of the invention. It is suilicient for the purpose of the invention that connections be used which establish a magnetic iluX and that means be providedv for detecting variations in the field thus created and, if desirable, for actuating an annunciator in response to such variations. More than one annunciator might be used. More than one indicator might be used in addition to the annunciator. The flux might be set up, not in a doorway or opening but at any desired point. In one arrangement a railing is used in a generally open space and the magnetic fluxis set up in the neighborhood of the railing.

The use and operation of our invention are as follows:

With the parts arranged as shown in Figures l and 2, or in any Way in which a magnetic flux is set up, the primary circuit will be energized by suitable current and induced current will thereby beset up in the secondary circuit. The parts of the secondary circuit will be so adjusted that the current is varied for the size of opening or air gap. The current is also adjusted to be affected by a suitable object. Thus it may be adjusted so that so small an object as a bunch of keys will not cause a sufficient change to actuate the annunciator and so that a larger object, such as a revolver, will cause a suiiicient change to actuate the annunciator or alarm and to cause an immediate movement in the current indicator, if any is used, suicient ,to be readily obvious to an observer. Thus if someone comes into the iield of the magnetic flux with such a metallic object, the air gap will be shortened, the secondary `circuit will be disturbed, in this case by having an increase in current, the current indicator, if one is used, will indicate this change in current and the annunciator willbe actuated. Thus a guard or observer will be notified atA once of the presence of someone in the vicinity carrying a relatively large object of iron or steel and such a person may be at once put under .observation. If the current or circuit is broken, the indicator, if used, will indicate that fact and the annunciator will again be actuated. This will take place whether the circuit is broken purposely or accidentally.

Assuming the circuit as shown in Figure 3 and in position as shown in Figure 1, the parts are balanced so that` the movable member E8 of the polarizedrelay is held in intermediate position, out of contact with either of the contact inembers adjacent it. If now an article such as a piece of metal Y is brought into the flux, the air gap .will be shortened and current will be increased. This will unbalance the relay so that the member E8 will swing to one side, for example, making contact with the member F. Thus through the circuit shown and described, the magnet H is energized, the member H3 is drawn to the magnet, vthe'member F6 is then free to move and make contact with the member F7, thusV completing the annunciator circuit is actuated. The variation in current caused by the presence of the article Y in the ux will, of course, have `shown on the indicator, if one is used. Thus the annunciator has been actuated and the indicator hasl also been actuated.

Iii-the circuit is broken, the current turned oi or the balance otherwise destroyed, the parts having been in the position shown in Figure 3 will again become unbalanced, the member E8 will move in the opposite direction, making contact for example with the member G, thus again completing the magnet circuit, energizing the magnet H and, as above described, permitting the member F6 to make contact with the member F'I to complete the annunciator circuit. Thus, once the parts are balanced, such variation of the current in either direction. either an increase or a decrease, will` act upon the relay to cause movement to complete the annunciator circuit and` of course, variation of the current is indicated on the indicator, if one is used. Frequently an indicator is not necessary. If so, an indicator is added to the circuit or the movable element E8 is so arranged that its position and movement can be seen. In that caseit serves as an indicator.

Ordinarily the annunciator will continue to ring or give Whatever signal it is arranged to give, until it has been reset. Thus it will continue to give its signal even after the member Y has moved out of the magnetic field. Where it is desirable, an automatic reset may be arranged which will resultin resetting the circuit and returning the annunciator to its normal position as soon as the object Y has moved out of the magnetic field.

Ihe device may be used with a series' of annunciators and they may be located anywhere. For instance, an annunciator might be located at a police station or at any other suitable point as well as adjacent the device.

We claim:

l. In an apparatus for detectingk the movement of metals permeable to magnetic lines of force through a zone of detection, a plurality of coils positioned laterally of and at the opposite sides` of said zone of detection, means for creating and maintaining therebetween and across said zone ofdetection an alternating current eld generally transverse to the direction of movement of metals through said zone, adjustable electrical means connected to one of the coils and eiective to accommodate variable transverse dimensions of the zone of detection, and also to accommodate variable bodies of metal, a signal, means connected with the signal and the adjustable electrical means to operate said signal upon "disturbance of the field ybyf presence of metal -thereirnandmeans in communication withl said adjustable'electricalfmeans and coup-led with said' 'signal loperating means tov initiate the signal operatingv'means upon the failure of the alternating current. n y

'2.'In an apparatus for detecting the movemetal,a signal,-means connected withl thesignal to operate same upon disturbance of the yeld by, movement of metal therethrough, and means ,invcommunication with said adjustable electrical means `and coupled with saidsignal operating means to initiate the signal operating means upon failure of the magnetic eld.

3. In an apparatus for detecting the movement 0f metals permeable to :magnetic lines of force through ay zone of detection, a plurality of coils positioned laterally of and at the opposite sides of Asaid zone of detection, means for creating 4. In an apparatus for detecting the presence of metals in a zone of detection, means positioned laterally of and at opposite sides of said zone of detection, alternating current means including said first means for creating and maintaining therebetween and across said zone of detection, a field generally transverse of said zone, adjustable electrical means connected kto one of the means positioned at opposite sides'of the zone of detection eifective to accommodate variable `transverse dimensions of the Zone of detection,

and also to accommodate variable bodies of metal, a signal, means connected withthe signal to operate same, and means inl communication with said adjustable electrical means and coupled with said signal operating means to initiate operation of the signal operating means upon disturbance of the eld caused by the presence therein of a body of metal.

5. In an apparatus `for detecting the presence of metals in a zone of detection, means positionedv laterally of `and at opposite sides of said zone of detection, alternating current means including said first means for creating and maintaining therebetween and ,across said Zone of detection, a iield generally transverse of said zone, adjustable velectrical means connected to one of the meansv positioned at opposite sides of the zone of detection effective to accommodate variable transverse dimensions of the zone of detection, and also to accommodate variable bodies of metal, a signal, means connected with the signal to operate same, and means in communication with said adjustable electrical means yand coupled 'with said' signal `operating'means to initiate operation ofthe signal operating-means upon disturbance of the field caused l by failure of the alternating current means which normally maintains the field.

6. In an apparatus for detectingthe presence of metals in a'zone of detection, means positioned laterally of and at opposite sidesof saidzone of detection, alternating current means including said rst means for creating and maintaining therebetweenl and across said zone of detection, afield generally transverse of said zone, adjustable electrical means connected to one of the means positioned at opposite sides of the zoneof detection effective to accommodate variable,

transverse dimensions'of the zone of detection, and alsoto accommodate variable bodies of metal, a .signal, means connected with the 'signal to operate same, and means in communication with said adjustable electrical means and coupled with said signal operating means to initiate operation of the field caused by the presence therein of a body of metalpor by failureof the alternating current means 'which' normallyv maintains the field. l 7. In anapparatus for -detecting the presence of metal on personspassing lthrough a doorway, means for creating an'd maintaining an alternating current eld' across -said doorway, and indicating means responsive to variations in said eld, due to presence therein of such metals, the means for creating and maintaining a field across said doorway including a coil on one side of said doorway, means for electrically energizing said coil, a second coil on the opposite side of said doorway, electrically energized by said first coil, and means connecting the indicating means to one of said coils wherebyy said indicating means will be operated by a disturbance or variation in the intensity of the field caused by the presence of such metals in the eld.

' ofthe signal operating means upon disturbance` Y 8. In an apparatus for detecting the presence y of metal on persons passing through a doorway, means for creating and maintaining an alternating current field across said doorway,.and indicating means responsive to variations in said field, due to presence therein of suchmetals, the means for creating and maintaining a field across said doorway including a coil on one side of said doorway, means for electrically energizing said coil, a second coil on the opposite side of 'said doorway, electrically energized by'said first coil,

and means connecting the indicating means to one of said coils whereby said indicating means will be operated by' a disturbance or variation in the intensity of the field caused by a failure in the electrical energization of said first member.-

9. In an apparatus fordetecting the presence of metals on persons passing through a doorway,

means for creating and maintaining an alternatone of said coils whereby said'indicating means will be operated by a disturbance or variation in the intensity of the eld caused by the presence of such metals in the eld, and by a failure in the electrical energization 0f saidrst member.

10. In an apparatus for detecting the presence of metals on persons passing througha doorway, means for creating and maintaining a eld across said doorway, and indicating means responsive to variations in said field due to movement thereinto of such metals, the means for creating and maintaining a field across said doorway including -a coil on one side of said door-- way, and means for electrically energizing said coil to vary the intensity of the eld to accommodate variations in the volume of the metals. to be detected, a second coil on the opposite side of said doorway, electrically energized by said first member, means 4connecting the indicating means to one of said coils whereby said indicating means will be operated upon a disturbance in the field by the movement of such metals in the eld, and means to adjust said connecting means `whereby to accommodate Variable trans- Verse dimensions of the field.

11. In an apparatus for detecting the presence of metals on persons passing through a doorway, means for creating and maintaining a eld across said doorway, and indicating means responsive to variations in said field due to movement thereinto of such metal, the means for creating and maintaining a eld across said doorway including a coil on one side of said doorway, and means for electrically energizing said coil to Vary the intensity of the field to accommodate variations in the volume of the metalsto be detected, a second coil on the opposite side of said doorway, electrically energized by said rst coil, means to adjust one of said coils to regulate and vary the density of the eld, and means connecti ing the indicating means to one of said coils' 4 Way, means for electrically energizing said coil,

a second coil on the opposite side of said doorway, electrically energized by said first coil, and.

means including a Vacuum tube translating device oonnecting the indicating means to one of said coils whereby said indicating meansl willbe operated upon a disturbance or variation in the 25 ntensity of the field by the movement olfr such metals in the eld.

JOHN C. BECKER. ORMONDE C. BECKER. ELLSWQR'ITH J. BECKER. 

